Opportunistic infections are a major cause of morbidity and mortality in AIDS patients. The human immunodeficiency virus is the main cause of immunodepression in these patients recently malnutrition has been implicated as a contributing factor. Therefore, minimizing any malnutrition-associated immune impairment might prolong health in AIDS patients. Restoring nutritional status of seriously ill patients is not always possible. Therefore, the ability of hormonal modifications to improve immune function and resistance to viral infection, independently of improving nutritional status, will be investigated. Evidence from anorexia nervosa patients indicates that exercise during undernutrition may be a physiological means of altering endocrine function so as to accomplish this. A mouse model of anorexia nervosa has been developed and will be used to investigate the effect of exercise - treadmill running - on resistance to cytomegalovirus (CMV) during under nutrition. Tissue levels of CMV will be used a measure of the severity of infection and the immune response to CMV will be quantitated by specific serum antibody and splenic cell-mediated cytotoxicity against CMV-infected fibroblasts. Other measures will include corticosterone, prolactin and brain levels of biogenic amines since we have previously found that each has immunomodulatory properties. Interleukin 1 will also be measured. In addition to addressing a particular clinical problem, these studies will provide basic science data concerning interactions between nutrition and the neuroendocrine and immune systems. As such, they contribute to similar interdisciplinary research ongoing in this laboratory.